This depends on a few things. Are you athletic? Obviously if you are athletic and losing much waterthrough prespiration through the day, you will need to consume more water.Are you eating fresh fruits and veggies that contain water? If you are mostly eating processed foods, you should drink more water than a person who is eating fruits and veggies on a regular basis. Are you thirsty often? When you feel thirst, you are already dehydrated. If you are thirsty often, drink more water through out the day.

To me, it is less important about the exact amount as much as when you drink water. Try to drink water at least every 3-4 hours. Drink water with every meal. Drink water after you drink anything else (for your teeth). Drink water when you get up in the morning. Drink water while you are drinking alcohol. Drink water when you are hungry. Drink water before you drink water and then drink some more.